Inactivation of pulmonary surfactant by silicone oil in vitro and in ventilated immature rabbits

Guido Stichtenoth*, Bim Linderholm, Andreas Almlén, Marie Hägerstrand Björkman, Irene Byman, Kerstin Nordling, Bengt Robertson, Jan Johansson, Egbert Herting, Tore Curstedt

*Corresponding author for this work
3 Citations (Scopus)


Objective: Surface activity of pulmonary surfactant is impaired by exposure to syringes lubricated with silicone oil (SO). These syringes are used daily in clinical practice. Design: In vitro experiments were used for detection of SO, determination of surface activity, and semiquantitative measurement of surfactant protein (SP)-B and -C in SO/surfactant mixtures. Randomized, controlled animal studies were applied for determination of in vivo activity. Setting: University research laboratory. Interventions: Mass spectrometry of SO originating from syringes with and without surfactant was performed. The surface activity of SO plus surfactant phospholipids (PLs) or modified natural surfactant (Curosurf) was measured. SO/Curosurf preparations were further analyzed for changes in the content of SP-B and SP-C using immunoblotting. Neonatal rabbits received mixtures of SO/Curosurf (ratio 0-1.3 mg/mg PL) intratracheally and were then ventilated with a standardized sequence of peak insufflation pressures. Tidal volume curves were recorded, gas volumes of excised lungs were measured, and histologic analysis was performed. Measurements and Main Results: Dissolved SO was found after rinsing syringes with organic solvents or Curosurf. Surface activity of Curosurf was significantly reduced after addition of 0.13-1.3 mg SO/mg PL. Immunoblotting revealed interference of SO with SP-B, but not with SP-C. With increasing SO/Curosurf ratios, patchy alveolar air expansion was observed, lung gas volumes were reduced, and time to inflate the lungs was increased, whereas compliance and tidal volumes remained unimpaired. Conclusions: In vitro SO impairs surface activity of Curosurf and leads to interference with SP-B. SO contamination of exogenous surfactant impairs lung function in animal studies and should be avoided.

Original languageEnglish
JournalCritical Care Medicine
Issue number5
Pages (from-to)1750-1756
Number of pages7
Publication statusPublished - 05.2009

Research Areas and Centers

  • Academic Focus: Center for Brain, Behavior and Metabolism (CBBM)


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